Buy cold email inboxes, authenticated before handover

What you are actually buying

An order is a hundred Microsoft 365 mailboxes on a single domain, provisioned and authenticated. Cold email mailboxes and cold email inboxes are the same product under two names, so if you arrived searching for one, this is the other. The work that decides whether the mail arrives is done before you touch it: the SPF record written and checked against the ten-lookup limit, DKIM keys published and signing enabled in the tenant, a DMARC policy in place, and every record queried to confirm it actually resolves.

The domain is yours after handover, whether you brought it or we registered it in your name, so the sending reputation you build on it stays with you. The mailboxes run in a Microsoft 365 tenant dedicated to that domain for as long as the subscription is active.

Every domain gets its own Microsoft 365 tenant, and a second domain is never added to an existing one. Microsoft caps external recipients per tenant rather than per mailbox, so a tenant shared between customers is a daily ceiling and a reputation shared with senders you cannot see. Keeping them separate protects your batch and our infrastructure at the same time, and why tenant isolation matters sets out the limits behind that in full.

What it costs

$30 per domain per month. That is $0.30 per inbox per month, or $0.10 a month for each email of daily capacity. One number, no tiers, no per-seat pricing, no minimum. Billing renews monthly, and a cancelled order runs to the end of its billing period. A domain is $12, charged once, if you want us to register one, and free if you bring your own.

Scaling is linear and worth stating plainly: N orders means N domains, N×100 inboxes and N×300 emails per day, at N×$30 a month. If you need 1,000 emails a day, that is four orders. The calculator on the homepage does the arithmetic from a target daily volume.

How much sending 100 inboxes carries

Three emails per inbox per day, so 300 per order per day. That rate is deliberately below what Microsoft 365 permits, because a platform cap is an abuse threshold rather than deliverability guidance. Filters build a behavioural profile of each mailbox and ask whether it looks like a person; three a day looks like a person, and the platform ceiling does not.

The reasoning behind that number, and how to size a pool from a target volume, is set out in how many cold emails to send per inbox per day.

What happens after you order

Deployment takes 24 to 48 hours. In that window the domain is registered or connected, the mailboxes are created, every authentication record is configured and verified, and the inboxes are connected to your sequencer with warmup started. After that the infrastructure is yours: you write the campaign and load the list.

What is not included

No sending platform, no lead lists, no copywriting, no managed campaigns. If you want those, this is the wrong purchase and saying so early is cheaper for both of us. What you get is the layer underneath them, which is the layer that quietly decides whether any of it works.

Warmup is initiated in your sequencer at handover and is yours to maintain from there. Inboxes are not sold pre-warmed.

What the infrastructure does and does not decide

Across 11 of our own campaigns on this same infrastructure, 26,698 leads contacted produced a 1.73% bounce rate. Bounce rate is the number provisioning is accountable for: it reflects whether the mailboxes exist, whether authentication passes, and whether the receiving side will accept the mail at all.

Reply rate over the same period was 1.9%, and it ranged from 0% to 4.1% campaign by campaign on identically authenticated inboxes. That spread is the honest statement of the limit: infrastructure controls whether mail arrives, not whether anyone wants to read it. The full numbers and method are published, including the campaigns that replied at zero.

Before you buy from anyone

Whoever you buy from, the same four questions decide whether the batch is worth having: whether authentication is verified rather than assumed, whether the domain ends up in your name, what the per-inbox daily rate is meant to be, and what happens when a batch arrives broken. Our answer to the last one is that a broken batch reported within 14 days is remediated or refunded; there are no performance refunds, because nobody can honestly promise inbox placement.

If you are still deciding between providers rather than ready to order, the buying guide compares published pricing across the category, and the free DNS records checker will tell you whether inboxes you already own are authenticated correctly.

Buying cold email inboxes: FAQs